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More tinkering with this to do, but I have quickly gained respect for
these sound card scopes - so far it's working a thousand times better
than my HP scope has - not that HP scopes are bad, mine is just seen
much better days!
Chris

Analog/Digital Storage Oscilloscopes

Norm

This would work if every message contained a
complete history of the
thread. That works well for private conversations
between two people,
but doesn't work when dozens of people may be
involved. It just wasts
storage space. Besides, how do we figure out with
reasonable effort
what part of that extended reply you are responding
to, if your
response appears above the entire history? The
previous post may run
several pages, alone. You are expecting a lot of
work from thousands
of readers when you could simplify their work with
10s of seconds of
effort. Your method tells them that your 20 seconds
saved is more
important than their collective man hours of work.

The sampling rates on the low-end digital scopes and pc scopes has kept me
away from them. for the $300 figure that was mentioned, you should be able
to get a very good working tektronix 4xx series scope. The 465 is probably
the most common, and easy to find a good working, clean unit. And as far
as recording, there are camera setups just for that which are also easily
obtained and used. you may wish to check out the Yahoo group "Tekscopes"
for more info.

This just showed up in the yahoo "Tekscopes" list:

"Greetings, all: I have a really nice 7704 that
isn't getting used. ???I hope
someone on the list can use it. ???Excellent cosmetic
and electrical
condition. ???200 mHz bandwidth. ???Asking $280 shipped
and insured CONUS (it's
pretty heavy!). ???I can send you a photo if you're
interested. ???Please reply
off list. ???Thanks for the bandwidth....Mike W2IY"

On Friday 06 October 2006 10:48 pm, LT Ron Wright
wrote:

Chris,

You can get 10:1 probes. All I've seen have a

switch for selecting

times 1 or times 10. Are there probles with this

scope. Most all

come with them. Also due to the high impedance of

a scope input if

you do apply to larger voltages it should not

damage anything, just

saturate the input.

I think it depends on what parts are connected to
that input, inside the
scope. That rating is rather low, so it suggests
that some semiconductor
device is the limitation there.

--
Member of the toughest, meanest, deadliest, most
unrelenting -- and
ablest -- form of life in this section of space, a
critter that can
be killed but can't be tamed. --Robert A. Heinlein,
"The Puppet Masters"
-
Information is more dangerous than cannon to a
society ruled by lies. --James
M Dakin

The fastest micro I know of that I can work with is 20mhz, so the 60mhz of
this "Simulated scope" is certainly good for the range of stuff I work with.

While I certainly do like storage and recording features, the
biggest gain for me is that I "Should" be able to trust the display.
I can't trust my real scope and that is a very bad thing :-(

On Sat, 07 Oct 2006 18:12:55 +0200, AnaLog Services,
Inc.
<wireline@...> wrote:

Even with a wonderful Tek digital scope, looking

at irregular relatively

fast events like pulses from radiation detectors

can be problematic. In

fact, troubleshooting any oddball, unexpected

signal can be much harder

with a digital scope than an old analog unit.

I agree with that! Especially with very fast
irregular signals which i
can't quite figure out i'll go to the analog scope
to see "what's really
there". You'll also sometimes get sampling artefacts
with digital scopes
which you need to identify and make the necessary
changes, that will
sometimes confuse a novice.
But i wouldn't really want to work analog all the
time, the cursors and
easy setup of the digital scope are just too
comfortable to miss out on.
If i had to choose one scope... i'd probably cheat
and go for one that can
be switched between analog and digital modes ;-)

ST

Even with a wonderful Tek digital scope, looking at irregular relatively fast events like pulses from radiation detectors can be problematic. In fact, troubleshooting any oddball, unexpected signal can be much harder with a digital scope than an old analog unit.

There is one other feature that I think is kinda neat with these USB units,
you can be up to 16' from the PC. If you have limited desk space you don't
have to have the bulk of the equipment right next to you.
Jim

There is one other feature that I think is kinda neat with these USB

you can be up to 16' from the PC. If you have limited desk space

have to have the bulk of the equipment right next to you.

Jim

----- Original Message -----
From: "Stefan Trethan" <stefan_trethan@...>
To: <Electronics_101@...>
Sent: Saturday, October 07, 2006 4:11 PM
Subject: Re: [Electronics_101] Re: How limitting do you think a

be if it were limitted to 35 volts?

On Sat, 07 Oct 2006 16:39:21 +0200, rtstofer <rstofer@...> wrote:

As Stefan points out, the 50 Msps limits the frequencies that can be
sampled. The absolute maximum signal that can be accurately sampled,
according to the Shannon Sampling Theorem, is 1/2 of the sample
frequency or about 25 MHz. And that requires that the signal be
periodic. All bets are off for one shot signals.

I don't think the shannon theorem is very useful when looking at

It can be applied for real-time sampling (like for audio) but it

apply to sampling scopes (equivalent time) for repetitive signals.

If you use many periods to sample a signal there is no requirement to
sample at least twice each period. You can sample now, and again 5

later plus t, and then ten periods later plus 2*t, and then 20 periods
plus 3*t, doesn't matter.
You can buy 100GHz sampling scopes with only 10Msps. Clearly not
fulfilling Shannon.
<>

Neither is it all that practical for real-time sampling scopes,

correctly apply it, which you did, to the highest harmonic you are

to need. But estimating which harmonic you might want isn't much more
accurate than guessing how many points you'd like to have in a

your signal.

To be pedantic, the sampling frequency only has to be twice the

of the sampled signal.

Leon

To be pedantic, the sampling frequency only has to be twice the *bandwidth*
of the sampled signal.
Leon